The present invention relates to an activation device for a vehicle seat adjuster.
A known vehicle seat adjuster includes two lock fittings that are unlocked with a pivoting movement of an activation device that is in the form of a hand lever, so that the seat back can be pivoted. Because the hand lever is a one-armed design to save space, i.e. it is pivotably supported at a position that is distant from its center of gravity, there is a risk, in the event of a crash, that the hand lever, by reason of its inertia, will perform an unintended pivoting movement, thereby unlocking the lock fittings.
Therefore, for an activation device for a lengthwise adjuster with a pivotable lever in the DE 196 28 716 A1, it is suggested that a spring is provided whose characteristic force curve rises sharply in the initial phase and then, after reaching a local maximum, shows a negative gradient allowing easy activation. However, in the event of sufficiently high crash forces, even the local maximum can be overcome, allowing the adjuster to unlock.
One aspect of the present invention is the provision of improvements to activation devices for vehicle seat adjusters. In accordance with this aspect, the activation device includes an eccentrically mounted hand lever for pivoting in response to manual activation of the hand lever, so that the pivoting of the hand lever unlocks the associated adjuster to thereby enable operation of the unlocked adjuster. The activation device also includes an acceleration-sensitive device operative for immobilizing and/or locking the hand lever in the event of a crash, whereby the unlocking of the adjuster is prevented in response to the crash. Preferably, the acceleration-sensitive device is mounted for moving from a first predetermined position into a second predetermined position in response to the crash; with the acceleration-sensitive device being operative for allowing the pivoting of the hand lever while the acceleration-sensitive device is in the first predetermined position, and the acceleration-sensitive device being operative for restricting the pivoting of the hand lever while the acceleration-sensitive device is in the second predetermined position.
By virtue of the fact that there is an acceleration-sensitive device to immobilize and/or lock the hand lever in the event of a crash, the hand lever, in the event of a crash, will be secured independently of the magnitude of the crash forces, so that the adjuster does not unlock. With reference to the hand lever being eccentrically mounted for pivoting, this means that it is pivotably supported at a position that is distant from its center of gravity. The acceleration-sensitive device will preferably be a pivotably supported pendulum element, which is also preferably pivotably supported at a position that is distant from its center of gravity in order to react sensitively to accelerations in a simple fashion. For modular construction, i.e. in order to make a single-unit activation device, the pendulum element is preferably pivotably mounted on the hand lever. A more rapid response of the pendulum element in relation to the hand lever is obtained by virtue of the pendulum element having less mass than the hand lever.
In a preferred construction, the pendulum element, in the event of a crash, works in conjunction with a frame-fixed component in order to lock and/or immobilize the hand lever. For this purpose, the pendulum element preferably has a convex-shaped rim which, when bearing against the frame-fixed component, produces a locking effect. The frame-fixed component, which is preferably also convex, may be an adjuster-fixed bolt, for example, which, when used, also serves as a stop for the hand lever.
The activation device, according to the invention, can be used for a vehicle seat, for example in an inclination adjuster, a height adjuster, a length adjuster, or in an unlocking device for seat legsxe2x80x94hereinafter also called an adjuster.